DE3908188C2 - Plastic injection molding tool - Google Patents

Abstract

A mould for injection-moulding a plastic lid onto the tube of a package for liquid is described. The mould has an inner mould and a two-part outer mould (2, 7), of which two steel mould parts (2, 7) can be brought together in a sealing manner and moved apart along a parting surface (12) by control drives. In this arrangement, the injection-moulding cavity is formed by a surface contour construction (17), arranged on the mould parts (2, 7). On the side facing away from the injection-moulding cavity, cooling spaces (19) are provided behind the surface contour construction (17). <??>In order to improve the performance of the package-producing machine, in particular by improving the cooling of the moulding surface, it also being intended for less expensive moulds to be used for the injection-moulding cavity, the invention provides that the cooling spaces (19) are bounded on at least one side by an insert (9, 11) which is fastened liquid-tightly in a recess (20) in the respective mould part (2, 7). <IMAGE>

Description

The invention relates to a tool for injection molding plastic, with an inner shape and a two-part outer shape, of which two molded parts essentially made of steel Can be sealed against each other along a separating surface by control drives and from each other are movable, cold rooms being delimited by an insert on at least one side, which is attached in a recess in the respective molded part in a liquid-tight manner, an injection pouring cavity by a surface contour structure arranged on the molded parts and a Counter-contour structure of an inner mandrel is formed and the cooling rooms on the injection molding cavity side facing away from the room are attached behind the surface contour structure.

For the production of liquid packs, especially for milk and juices (food) it is already known, a lid with a pouring opening - and possibly even at the same time molded on the handle - on the paper tube coated on both sides with plastic to spray, because such liquid packs for the manufacture and also for the Bring benefits to end users.

The injection of plastic lids onto the paper tube takes place in the paper production machine of the known. Kind by means of an internal shape, which is essentially a cylindrical mandrel is trained who sits together with three other thorns on a mandrel wheel and during the Operation is intermittently progressed, with a mandrel or an inner shape in each case Injection is stopped and two molded parts of to form the injection molding cavity so together on the outside essentially perpendicularly over the free end of the inner shape drive that they can be sealed to each other by appropriate control drives and with Pressure pressed against each other and held in this position or possibly by others Tool parts are locked. The injection molding cavity formed in this way can then the suitable plastic can be filled under pressure so that the desired packing part, e.g. B. the lid or the lid with molded handle, are formed by injection molding.

The expert knows from his practice and from the literature about such injection molding machines, that the surface contour structure is complicated and manufactured with relatively great effort is why in particular the outer shape - and here each of the two molded parts - is expensive and should have a long service life. It is precisely with the two that form the outer shape  Molded parts, on the one hand, stability and cooling, on the other hand, are important. Kick during injection molding not inconsiderable pressures from the plastic from the injection molding cavity to the outside Boundary walls, namely the surface contour structure. If you feed the cold rooms close behind the surfaces that make up the surface contour structure, then these can be deformed by the high pressure. For security reasons, one is therefore kept certain distance from the cold rooms to the surfaces of the casting cavity. As a result of Forming the molded parts from steel is also the thermal conductivity of the ent speaking spaced cooling space to the surface contour structure limited. While using workpieces such as. B. the moldings from the outside quite well can process (e.g. the complicated surface contour structure), the cold rooms are Holes created. As is well known, drilling cannot be done with any precision lead into the inside of a molded part. For this reason, it is advisable to drill the holes at a minimum safety distance from the surface contour structure of the respective molded part hold. The arrangement of the cold rooms with respect to the surface contour structure on the one hand and the material of the molded part made of steel on the other hand result in insufficient cooling, so that the performance of the injection molding machines cannot be increased to the desired extent.

Another disadvantage is due to the fact that it is subject to general operating wear After a certain period of time, the entire molded part must have its surface contour construction to be replaced by a new one to ensure flawless molded parts on the packs to guarantee.

A tool is similar from the special print from plastic processor, issue 12/1967, pages 8, 9 of the type mentioned above. The injection molding cavity described there is indeed through formed a surface contour structure, but the cooling rooms are located at a large distance in the same body that carries the surface contour structure. The performance of one with one such an injection mold designed tool is quite limited because the cooling of the actual forming surface leaves something to be desired.

From the Plastics reference, October 1966, pages 1284-1288 is also an injection molding machine known stuff. There, however, the surfaces of the injection molding cavity are essentially flat Surfaces assembled and have a simple structure without contours. Furthermore the injection molding cavity is between inserts that are smooth next to the cavity. The In the known case, cold rooms are located either in the inserts themselves or outside behind this.  

Furthermore, DE 28 38 634 A1 describes an annular mold cavity for an annular one Cast body known. There are disadvantageous punching devices required to after Injection molding process to separate sprue parts from the annular casting. It is about Video discs, i.e. recording media with a central opening and a spiral track, as in Find records.

The invention has for its object a tool for injection molding plastic of the type mentioned to improve so that the performance of packaging manufacture machine can be improved because the cooling of the molding surface or surfaces contour structure is improved, preferably also cheaper tools for the Injection molding cavity to be used.

In connection with the preamble of claim 1 this object is achieved in that the use as approximately trapezoidal Plate is designed, which is mirror-symmetrical with respect to the parting surface formed plate of the other molding essentially one half of the injection molding cavity covers from at least one side.

If there are smaller injection molding cavities, then can these completely formed by two of these mirror-symmetrical plates and be covered. But is it, for example, an injection molding cavity, one of which Part of the lid and the other part of a handle molded onto the lid or Space for the plastic forming these parts, then a pair of inserts is often enough not out, and you then get two pairs of bets in the appropriate position to each other arrange. It has been shown that the plastic volumes to be cooled ultimately also Lids of a liquid pack are flat and thin spaces, so that one behind the Surface contour structure arranged cold room system this flat thin injection molding cavity should essentially completely cover the room. When packing liquid packs in It is advisable to make the insert trapezoidal in packaging manufacturing machines, especially in the case of such a type of package, which also has a plastic lid the plastic handle is to be molded onto the paper tube. The handle is from Tube material, d. H. from the paper, at a distance of 1 cm to 3 cm and preferably about 2 cm, so that in side view of the handle the entire surface forming the handle is best by a trapezoidal plate is covered. If a pair is used as suggested above of operations, d. H. a pair of trapezoidal plates, then essentially that Injection molding cavity for the handle covered, and this is essentially the half of the injection cavity.  

In a preferred tool, a very convenient embodiment of the invention can the pair of trapezoidal inserts on either side of the interface between the two Arrange molded parts in such a way that the trapezoidal shape is perpendicular to the viewer when looking the interface appears, with another pair of trapezoidal inserts on either side of the Partition surface is arranged such that the trapezoidal shape parallel to the viewer in the viewing direction the dividing surface appears from above or below. For injection molding essential parts of the handle the lid, in particular in connection with the pouring opening of the lid, takes place So cover another pair of inserts, the shape of which is essentially the same can be trapezoidal, but here the viewer sees the trapezoidal shape vertically in the viewing direction appears on the lid, d. H. in the direction of the parting surface and in the direction of the longitudinal axis of the Paper tube. This pair of inserts in the area of the pouring spout of the opening device on Lid is thus arranged side by side, with the one insert of the latter pair doesn't need to touch the other. Both inserts are arranged side by side and again cover the essential parts of the surface of the lid to be cooled.

It is also advantageous according to the invention if the cooling space is a substantial part of the Use takes and web-like support parts are arranged in the cold room. The volume of the The cooling space is large in terms of the material of the insert, which results in a very high cooling effect is achieved. The refrigerator compartment is interrupted by web-like support parts, and thereby the insert receives high mechanical stability. So though behind the whole surface contour structure in the area of the application arranged a large area of a cold room system is, high injection pressures can still occur in the injection molding cavity without the use would be damaged and the mold surfaces would bend.

The increased performance of a packaging machine is the most surprising result of the Measures according to the invention, because there were shortages in the simple means The cooling time of the outer mold of the injection mold is overcome. At the same time, the cold room system stem with milling tools can be designed very appropriately, and the cold rooms can quite are brought close to the critical cavities for injection molding with the consequence of a good heat dissipation and effective cooling of the injection molding cavity. By suitable Selection of the feed material can increase the thermal conductivity and thus the cooling effect increase further. The economy of the injection mold can also be improved in this way because the part that is most subject to wear is the actual injection mold, the is at least partially formed by an insert. After corresponding, normal wear and tear The measures according to the invention only require use by a new one to be replaced, but not the entire injection mold.  

It is therefore advantageous according to the invention to use a tool for injection molding Plastic, with an inner shape and a two-part outer shape, two of which in essential molded parts made of steel sealing along a parting surface by control drives can be put together and moved away from each other, an injection molding cavity through a is arranged on the molded parts arranged surface contour structure and on the Injection molding cavity opposite side behind the surface contour structure cold rooms are attached, which are bounded on at least one side by an insert in a Recess in the respective molded part is liquid-tight, for injection molding of the lid and / or bottom with or without a handle on the paper tube of a liquid pack.

According to the invention, the cold room or the cold rooms are no longer through bores in the interior of the steel molding but can be directly from an open side Tool accessible to be made, because the open side is limited by an insert. Either the cold rooms are installed on one side of the insert, or the insert closes the cold rooms on the surface of the steel molded part from the outside from. In the respective molded part there is a recess in which the insert is inserted and is attached, namely liquid-tight, so that, for example, cooling water, which by suitable channels are supplied to and removed from the cold rooms, can flow. The Attachment can be done for example by screwing. In other words, it is Insert screwed to the molded part next to the cold rooms.

Even a complicated cold room system can be produced by milling, because that Milling tool placed on a flat surface next to the cold rooms and from here into the Material can intervene. Either the cold rooms are milled into the insert itself, or the cold rooms are milled into the molded part, and the flat surface of the side that is then open the cold rooms are covered by the insert. You can see the whole area of the Cover the cold room system and consequently also produce it easily beforehand. You become one or the other choose another embodiment depending on the stability of the surface in question contour construction is required.

If a surface of the attached to the molding and made of a material with larger Thermal conductivity as a steel insert with part of the surfaces of the molded part ends flush, the greater thermal conductivity of the insert brings with it cooling advantages. in the Contrary to the holes, which sometimes run and therefore at a safe distance from Surface contour structure can be kept tight by milling into all rooms get next to the injection cavity, d. H. one comes close to that later with plastic  filled and strongly cooled areas. The surface contour structure is more understandable most likely to wear through wear. If this is in use, you need it can only be replaced by a new one without having to replace the entire molded part. Of the Use itself is easier and cheaper. In another embodiment, this is Cold room system in the steel of the molded part directly behind the surface contour structure open back of the cold rooms is covered by the better heat-conductive insert, which ensures an even better dissipation of the heat absorbed by the coolant.

In a second alternative embodiment, namely the one in which the cold room or the Cold rooms are milled in the molded part and are and the free side with the flat surface of Insert is covered liquid-tight, the insert has an inner flat surface, which limiting the cold room liquid-tight on the flat surface of the same Cooling space-receiving molded part rests. The cold room system can, for example There are spiral or serpentine grooves, between which webs have remained are on the outer surface, which then forms the common flat surface, the Use is supported. Due to the smooth, flat surface on which the insert is supported, you can use the milling tools and the cold room grooves when manufacturing the molded part Work out the steel in the desired pattern, keeping the cold rooms tight bring behind the surfaces of the surface contour structure.

The insert provides a kind of closure for the recess in the like a plug or lid respective molded part or sealing cover of the one below it, on one side before hanging up of the insert open cooling space. The respective outer surface of the insert can be with the close the adjacent outer surface of the molded part flush.

In a preferred embodiment, the cooling space is provided by grooves milled into the molded part webs arranged between them and the outer surface of the webs and the Edging of the grooves forms the flat surface of the molded part on which the insert rests.

Another alternative embodiment is also conceivable, in which the backlash-free Molded insert has an inner flat surface, from which starting extends at least one cooling space into the material of the insert, the insert being opposite lying has an outer flat surface that part of the parting surface of the molded part forms and has the surface contour structure of the injection molding cavity. At this Embodiment, the outer flat surface is expediently flush with the adjacent one Surface of the molded part be formed because the entire, over both parts (insert and  Molding) common surface on the parting surface of the two-part Injection mold (the two molded parts) rests. It is understood that the surface con structure of the injection molding cavity from this part of the outer flat surface was worked out, preferably by milling. While in the above Embodiment the cold rooms were milled into the steel takes place in this embodiment milling from the material of the insert. If the insert is made of aluminum, for example, then the surface of the contour structure is an aluminum surface. In other words the injection cavity is formed on both sides by the aluminum inserts. Of course you can but you can also imagine other good heat-conducting materials, preferably because of metals of stability.

Common to both embodiments is the good possibility of attaching the refrigerator compartment or compartments me to achieve a favorable cooling effect and the cooling liquid as close as possible to the Forming surfaces, d. H. to the surface contour structure, to bring the heat of dissipate this structure. However, this can be used to measure the performance of the packaging machine increase, because the cooling of the outer mold consisting of the two molded parts is successful the measures according to the invention faster with the result of increased performance of the machine equipped with this injection mold.

The preferred embodiment can be designed so that the cooling chamber is in use milled grooves with ridges arranged between them and the outer surface the ridges and the border of the grooves form the inner flat surface of the insert, via which the insert is liquid-tight against the flat surface of the recess in the molded part can be pressed. While in the embodiment described above, the insert is like a lid or plug has closed the grooves in the steel body and possibly on several sides can have flat surfaces, in the embodiment described here, the insert on the one hand the surface contour structure to form the injection molding cavity and on the opposite side of the cooling system is a surface with grooves and in between arranged webs on. The webs can be seen in a top view perpendicular to this inner plane Have a wide variety of shapes looking towards the surface, e.g. B. trapezoidal, circular, oval, elongated or the like. In any case, they form the support of the insert on the level Surface of the recess in the molded part, so that the surface contour build-up from Molding is supported. It can be seen that, despite use, a tool with high Possible stress is created.

Further advantages and possible uses of the present invention result from the following description of preferred embodiments in connection with the attached drawings. Show it:  

Fig. 1 shows in perspective a preferred embodiment of a liquid pack with lid and handle angepsritztem for illustration of the final product, which is produced by the injection molding tool to be described, who is the,

Fig. 2 is a top view of two mirror image substantially with respect to the middle parting surface aufgebau th mold parts with the inserts,

Fig. 3 is a side view of the left mold part of FIG. 2, for example when one ent the right mold part removed and looks up the separating surface,

Fig. 4 shows the use in the area of the handle from the side of the cooling chamber forth

Fig. 5 is a sectional view taken along the line BB of Fig. 4,

Fig. 6, the other view of the insert, with respect to Fig. 4 from the opposite side with the surface contour depicting lung structure,

Fig. 7 is a sectional view taken along the line AA of Fig. 6,

Fig. 8 in two different sectional views, the molded parts, if one looks in Fig. 2 from the bottom up, the section along the line CC of Fig. 9 is genom men and

Fig. 9 is a partially sectioned plan view of the mold parts similar to Fig. 2, however, the Kühlraumsyste me can be seen in the region of the lid with the pouring device.

In Fig. 1, the product of the Packungsherstel processing machine, ie the package itself, is shown in order to improve the understanding of the injection molding cavity to be described later and also to improve the other tool parts. The package shown in Fig. 1 consists of a paper tube 1 with a square cross-section, its bottom edge 3 having the width a and the length a, that is, spanning a square. On the opposite side of the tube 1 is the generally designated 4 cover, which is molded from plastic onto the plastic-coated paper material of the tube 1 . Together with the lid 4 is its opening device molded 5 with its pull tab 15 and on the opposite side of the handle 6 with gripping opening 10th It can be seen that the surface F formed from paper next to the handle 6 is at an angle to the plane of the cover 4 . The perpendicular through the plane of the lid 4 longitudinal central axis of the Pac kung and the tube 1 is shown in phantom and designated 8 .

Regarding the cooling of injection molded plastic, the part of the handle 6 facing away from the triangular surface F is particularly critical because the plastic supports itself and is not molded onto paper surfaces, as is the case in the area of Dec 4 .

It is the injection molding cavity for the handle 6 to cool especially, but also the lid 4 with the opening device 5 and the tear tab 15 is to verse hen with improved cooling.

Therefore, Fig. 2 shows in plan view of the molded parts 2 and 7, the first pair of inserts 9 and 11 with a trapezoidal shape in the direction of the longitudinal central axis 8 , which runs through the parting surface 12 , and the second pair of inserts 13 and 14 , the trapezoidal shape is Figs. 3, 4 and 6 in a view perpendicular to recognize the separating surface 12.

The outer shape of the injection mold is thus formed by the two mold parts 2 and 7 . In Figs. 2, 8 and 9 we see how the mold parts 2 and 7 by not dargestell th control actuators with pressure along the separating surface 12 are pressed against each other sealingly. This results in an injection molding cavity 16 , which is only partially visible in FIGS. 6 and 7. In the other representations, one mostly looks at the surface contour structure 17 , the counter-contour structure of the inner mandrel is missing, because this is not shown. For example, you can see in the right half of the sectional view of FIG. 8, a cavity under the surface contour structure 17 , in which the inner mandrel, not shown, can be inserted. The injection molding cavity 16 then adjoins in FIG. 8 on the right below the line representing the surface contour structure 17 .

While in the conventional tools the cooling rooms could only be formed by bores, as shown here in the construction according to the invention, the cooling water channels 18 are shown, which only create the inlet and outlet for cooling water in the embodiment shown here, the cooling room is or are Cold rooms 19 milled here.

Two different embodiments of inserts 9 , 11 on the one hand and 13 , 14 on the other hand are shown below, FIGS. 2, 8 and 9 relating to the inserts 9 , 11 for better cooling of the lid 4 with pouring device 5 , and that Pair of inserts 13 and 14 will be explained with reference to FIGS. 2 to 7, the cooling in the region of the handle 6 being discussed here.

The recess 20 in the molded part 9 , 11 or 13 , 14 is common to both embodiments of inserts. In both types of operations 9 , 11 ; 13 , 14 adjoin the cooling rooms to a flat surface, specifically in the embodiment of the inserts 9 and 11 to the flat surface 21 ; and in the use zen 13 , 14, the flat surface 21 ', which is also the base of the recess 20 in use 13 and 14 respectively.

In the plan view of Fig. 6 with the injection cavity 16 of the viewer looks practically to the outer surface 22 of the insert 13, in which even the surface of structure 17 forms ge is. This surface 22 of the molded part 2 , 7 to be BEFE increasing insert 13 or 14 is flush with part of the surface 12 of the molded part 2 , 7 , because this upper surface 12 of the molded part is also the parting surface 12th

This is different in the embodiment of inserts 9 , 11 , which will now be described in particular with reference to FIGS. 8 and 9 be.

The insert 9 or 11 , which is preferably made of aluminum, has an inner flat surface, which is designated by 21 , because it coincides with the flat surface to which the cooling chambers 19 located below are adjacent. This is also the flat surface of the molded part 2 or 7 . One can see in particular from the top view of FIG. 9, in which the inserts 9 and 11 are removed, as serpentine-like grooves 19 'are milled into the steel of the molded part 2 and also 7 , webs 22 arranged therebetween being left together with the border 23 of the grooves 19 'form the aforementioned flat support surface 21 . Also on this is a set 9 , 11 liquid-tight.

Looking in Fig. 1 from the top left of the pouring tip of the opening device 5 , then Fig. 8 is the corresponding tool for the lid the corresponding view. The upper middle point of the two molded parts 2 and 7 is in the vicinity of the tip of the opening device 5 shown in dashed lines in Fig. 9 5th It can be seen how the trapezoidal surface, the tip of which is opposite the other surface of the pair of inserts, covers the critical surface to be cooled. From Fig. 8 you can see how close the cooling space 19 or the Nu th 19 'to the mold surface, which is the surface contour 17 , approach.

In operation, cooling liquid can be brought up or discharged through the cooling water channels 18 and flow channel-like through the grooves 19 'in such a way that the heat generated by the spraying of the plastic is rapidly dissipated and the plastic is sufficiently hardened in a short time. When the lid and handle are sufficiently hardened, the two molded parts 2 and 7 together with the inserts 9 and 11 attached to them can move apart, the movement with respect to the separating surface 12 being symmetrical and the package then being able to be turned out laterally, for example according to FIG. 2 and 9 upwards or downwards in the direction of the separating surface 12 .

The other embodiment of inserts 13 and 14 can be seen mainly from FIGS. 2 to 7. The cooling space of FIG. 3 is formed over a large area and has, for example, a trapezoidal support surface in the middle, which is referred to here as the web 22 because of the uniform designation , if there is no exact web shape. Such a support body as the body shown at 22 in FIGS. 3 and 4 can also have other outer contours, for. B. circular, oval, win kelig or the like. It is useful for reasons of stability to take on the high spray pressures, in addition to the central web 22 , further, not shown here, Druckauf receiving webs. These webs 22 extend from the bottom of the cooling space 19 , ie in the view of FIG. 2 from the surface 20 or 21 ′ to the height of the separating surface 12 .

In the viewing direction to the parting face 12 the Betrach the trapezoidal shape shown in Figures 3 appears clearly ter., 4, and 6. Ent is speaking, the border 23 'of this insert 13 and 14, respectively trapezoidal. It is particularly thick on the mounting holes 24 . In Fig. 6 you can already see the anchoring screws 25 , which extend through the mounting holes 24 in the border 23 '. In Fig. 4 he is also known a sealing cord 26 which is inserted into a shallow groove 27 shown in Fig. 5 in order to arrange the insert 13 or 14 liquid-tight on the bottom of the recess 20 in the molded part 2 , 7 . Only then can cooling water in operation in the desired manner introduced into the cooling space 19 and z. B. on the opposite side again without affecting the current spraying operation. It is stig gun when, as shown in FIG. 4, the sealing cord 26 are all mounting holes 24 outside leaves in the border 23 'at rated or extends inside the same.

In order to get as close as possible to the shaped surface or the surface contour structure 17 of the injection cavity 16 from the large cooling space 19 according to FIGS. 4 and 5 at particularly critical points, in the embodiment shown in FIGS . 5 to 7 there are additionally deepened grooves 19 'a milled so that the distance from the bottom of these grooves 19 ' to the surface contour structure 17 is so small that heat is dissipated well from the injection molding cavity 16 , especially since the insert 13 or 14 is made of a highly thermally conductive material, e.g. B. aluminum.

Fig. 6 shows the top view of (with reference to Fig. 4) on the right side of the insert 13 , namely looking at the surface contour structure 17 . An injection molding cavity 16 can be seen , which after filling with plastic, hardening and removal of the tool corresponds approximately to the handle 6 of the package of FIG. 1. In the special embodiment, he must give this handle exactly.

How small ribs 27 are provided for stiffening on the handle 6 for better demolding and are therefore also arranged in the tool according to FIG. 6 can be seen clearly on both sides of the separating surface 12 in FIG. 7.

In operation, the inserts 9 , 11 and 13 , 14 are screwed to the mold halves 2 , 7 , the cooling water channels 18 are connected, and then all the cooling rooms 19 are flowed through with cooling water. Wear parts 13 and 14 in particular can be easily replaced.

Claims (4)

1. Tool for injection molding of plastic, with an inner mold and a two-part outer mold ( 2 , 7 ), of which two molded parts ( 2 , 7 ) essentially made of steel can be sealingly placed against one another and moved away from one another by control drives along a separating surface ( 12 ), cooling spaces ( 19 ) being delimited on at least one side by an insert ( 9 , 11 ; 13 , 14 ) which is fastened in a liquid-tight manner in a recess ( 20 ) in the respective molded part ( 2 , 7 ), an injection molding cavity ( 16 ) is formed by a surface contour structure ( 17 ) arranged on the molded parts ( 2 , 7 ) and a counter contour structure of an inner mandrel and the cooling spaces ( 19 ) are arranged on the side facing away from the injection molding cavity ( 16 ) behind the surface contour structure ( 17 ), characterized in that the insert ( 9 , 11 ; 13 , 14 ) is designed as an approximately trapezoidal plate which, together with the plate ( 12 ) Mirror-symmetrical plate of the other molded part ( 2 , 7 ) essentially covers half of the injection molding cavity ( 16 ) from at least one side. 2. Tool according to claim 1, characterized in that a pair of inserts ( 13 , 14 ) in trapezoidal shape on both sides of the separating surface ( 12 ) between the two molded parts ( 2 , 3 ) is arranged such that the trapezoidal shape perpendicular to the viewer in the viewing direction the dividing surface ( 12 ) appears, and that a further pair of inserts ( 9 , 11 ) in a trapezoidal shape are arranged on both sides of the dividing surface ( 12 ) such that the trapezoidal shape appears to the viewer in the direction of view parallel to the dividing surface ( 12 ) from above or below. 3. Tool according to claim 1 or 2, characterized in that the cooling space ( 19 ) is mounted over a large area in the insert ( 13 , 14 ) in such a way that it takes up a substantial part of the insert ( 13 , 14 ), and that web-like supporting parts ( 22 ) are arranged in the refrigerator ( 19 ). 4. Use of a tool for injection molding of plastic, with an inner mold and a two-part outer mold ( 2 , 7 ), of which two molded parts ( 2 , 7 ) formed essentially of steel along a separating surface ( 12 ) by control drives sealingly against each other and from each other are movable, wherein an injection molding cavity ( 16 ) is formed by a surface contour structure ( 17 ) arranged on the molded parts ( 2 , 7 ) and on the side facing away from the injection molding cavity behind the surface contour structure ( 17 ) there are cooling spaces ( 19 ) which are arranged on at least one Side are limited by an insert ( 9 , 11 ; 13 , 14 ) which is fastened in a liquid-tight manner in a recess ( 20 ) in the respective molded part ( 2 , 7 ), for injecting the lid ( 4 ) and / or base with or without Handle ( 6 ) on the paper tube ( 1 ) of a liquid pack.